Rotary forced contact type air switch



May 1, 1951 M. KUWAYAMA ROTARY FORCED CONTACT TYPE AIR SWITCH Filed June so, 1949 fiIHJaT Qm /lown yomn MW, fgL/ fatented May 1, 1951 ROTARY FORCED CONTACT TYPE AIR SWITCH Masatoshi Kuwayama, Taga, Taga-Gun, Japan, assignor to Hitachi Limited, Tokyo, Japan, a

corporation of Japan Application June 30, 1949, Serial No. 102,218

3 Claims. 1

This invention relates to rotary forced contact type air switches, and more particularly to the operating mechanism thereof, and has for its object to provide a simple construction and arrangement to be easily manufactured at a reduced cost and effecting light and smooth switching operation.

With the above object in view the present invention consists of novel details of construction and arrangement of parts hereinafter fully described and claimed.

Referring now to the drawing;

Figure 1 is a perspective view of essential parts of a rotary forced contact'type air switch embodying this invention showing the parts in an open circuit position,

Figure 2 is a side view of the toggle link mechanism adopted for the air switch in a stretched condition,

Figure 3 is a perspective view similar to Fig. 1 showing the mechanism in a closed circuit position, and

Figure 4 is a side view of the toggle link mechanism in a collapsed condition when the circuit breaker in closed.

Now referring to the drawing, I represents a stationary contact member which is fixed to a post insulator, not shown, having a lug 2 projecting therefrom. 3 represents a movable contact bar having a contact blade 4 at one or both ends and a small rod 5 projects from the bar at an eccentric position with respect to the blade. The bar 3 is secured to an axle 6 supported by a bracket I which is rotatably supported on a vertical post 9 by the sleeve 8. The post 9 is fixed to a metallic base plate It secured to a supporting insulator II. The insulator II is arranged to be operated either manually or by some power transm'itting mechanism such as a pneumatic motor, not shown, in case of switching operation of the circuit breaker. I2 represents an operating arm fixed to and projecting from the base plate It). The end of the arm I2 is connected by means of a toggle link mechanism consisting of forked lever I5l6 to a bracket arm I3 of the bar 3. One end of the forked lever H5 is pivoted on a horizontal axle I8 while the other end of the forked lever l5 has a universal joint consisting of axles I1 and I4 pivoted to the bracket arm I3.

The operation of the above described mechanism is as follows:

At the open circuit condition of the air switch shown in Fig. 1, the toggle link mechanism including the parts I3, I4, I5, I6, I1, and I8 is in the position as shown in Fig. 2 lying on a straight line and having the dead center on the axle I4. Accordingly if the supporting insulator I I is turned in the direction shown by the arrow in Fig. 1, the operating arm I2 fixed to the insulator I I is turned in the same direction together with the insulator. Then the arm I2 turns the bar 3 horizontally about the vertical post 9 by means of the toggle link mechanism I5-I6 and the bracket arm I3, and the contact blade 4 the end of the bar 3 is moved into the stationary contact 5. When the rod 5 engages on the lug 2 during the above movement of the bar 3, the latter is turned about its own supporting axle B in the direction shown by the arrow in Fig. 2 so that the toggle link mechanism is collapsed since its dead point is lifted, as understoodfrom Figs. 2 and 4. Further movement of the supporting insulator I I in the same direction forcibly turns the bracket arm I 3 in the same direction by means of the operating arm I2 and forked link I5I 6 acting on the bracket arm I3.

The contact blade 4 is not put in forced contact with the stationary contact member I if the blade 4 is merely moved into the latter, yet when the blade carrying bar 3 is turned about its own axis for about degrees at the shifted position as above explained, the fiat edges of the blade 4 can be forced to make contact with co-operating surface of the stationary contact. When the circuit closing operation has been accomplished the toggle link mechanism takes the collapsed condition as shown in Fig. 4.

Next when the air switch is required to be operated from the above described closed circuit position as shown in Fig. 3, the supporting insulator II should be turned in the opposite direction. Then the operating arm I2 pulls the bracket arm I3 to the left referring to Fig. 4 by means of forked link I5-I6, and the bar 3 carrying the contact blade 4 is turned counterclockwise for about 90 degrees about its own supporting axle B so that the blade 4 can be released from its forced contact. Then the further turning movement of the supporting insulator I I in the same direction completely disengages the blade 4 from the stationary contact I and all parts are brought to the circuit open position as shown in Fig. 1. The distance between contacts at the open position can be suitably selected to provide sufficient insulating distance, for instance, by turning the bar 3 horizontally for about 90 degrees from its closed circuit position.

It has heretofore been proposed in such types of electric switch that the moving contact blade be turned horizontally by the supporting insulator to be brought into a stationary contact member and then the blade is turned for about 90 degrees at that position to develop contact pressure. But in such known electric switches complicated operating mechanisms such as gearings, springs etc. have to be provided between the base plate I0 and the blade bar 3 and moreover some means for holding the revolution of the gearing under a certain condition is necessary. Accordingly they have many operating parts which are difficult to manufacture so that the cost is increased.

According to the present invention the operating mechanism is originally improved by using a simple toggle link mechanism as the connection between the base plate [0 and the blade bar 3, so that cost of material and labor can be reduced to about some tenths of the former electric switches of this kind. This invention has the advantage of providing light and smooth operation, thereby reducing the capacity of operating power source and simplifying the design.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric switch comprising a fixed contact, a rotatably mounted supporting insulator, a metallic base plate fixed to the insulator, a movable contact bar mounted on the base plate to swing in a plane parallel to its own longitudinal axis and perpendicular to the axis of rotation of the insulator and to rotate about an axis parallel to its own longitudinal axis, an operat ing arm projecting from the base plate, a toggle connecting the operating arm to the contact bar, and complementary lugs on the fixed contact and the contact bar operative to become engaged and to initiate rotation of the bar about said parallel axis when swung through said plane thereby to break the toggle link from extended position and continue rotation of the bar into a position of engagement with the fixed contact.

2. An electric switch as in claim 1 including a stanchion mounted on the base plate, and a bracket pivoted on the stanchion, the contact bar being journalled in the bracket for rotation about said parallel axis.

3. An electric switch as in claim 1 wherein the toggle comprises a bracket fixed to the contact bar, and a link pivotally connected at one end to the bracket for pivoting movement about two mutually perpendicular axes and at the other end to the operating arm.

MASATOSHI KUWAYAMA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,695,868 Stolz Dec. 18, 1928 2,420,074 Froland May 6, 1947 

